Numerous systems have been developed for the handling of cargo materials, such as crated or boxed items. Devices for the handling of such materials are particularly necessary at warehouses and at loading and unloading docks; whereat large volumes of cargo may be involved.
One widely used method of cargo handling is through the utilization of hand trucks, forklifts, and similar trolley arrangements. While such devices have their uses and advantages, they are not particularly effective for use when it is necessary to move large numbers or volumes of boxes, crates and the like along a repeated path. For example, the movement of 1,000 crates across a single path, into a railroad car, would generally require 1,000 trips with a hand truck or forklift, or at least a plurality of such trips if more than one crate could be handled at a time.
Further, such hand trucks and forklifts may require physically demanding loading and unloading operations for their own use, or at least a proper stacking of the material on a pallet or the like. Also, their use may be hampered when operating space is limited, or when environmental conditions are inclement.
Conveyor systems are often utilized when movement of materials along a repeated path is desired. While such devices certainly have their uses and benefits, they are limited due to numerous drawbacks, outlined below. The term "conveyor" when used with respect to these devices is generally meant to refer to conventional roller conveyors, belt conveyors and the like, on which boxes, baggage or other materials are typically transported along a moving or rotating surface.
Problems with such arrangements include that they are relatively complicated to set up, and are usually somewhat permanent in their positioning. That is, a single path can be readily defined by such devices; however, the path cannot generally be readily changed without substantial disassembly and reassembly steps. Further, operation of many such assemblies requires a construction such that the upper or transport surface of the device is raised considerably, in relief, from the warehouse floor or other surface involved. A problem with this is that the cargo must be lifted onto such surfaces, which can require considerable energy and/or special handling equipment.
Further, such devices are not particularly well-adapted for the transport of material into and out of trucks, railroad cars or the like. A reason for this is that such conveyors often terminate at the end of the loading dock, and do not operate effectively to move the cargo completely into, or out of, the enclosed spaces represented by the truck, trailer or other vehicle.
Another problem with such devices is that they often are very complicated, and subject to breakdown at any of numerous points therealong. That is, failure of a roller, bearing or the like can sometimes jam-up or stop the entire system.
What has been needed has been a system usable to convey materials such as crates or the like over a surface such as a warehouse floor; and, further, a system wherein the material can be readily transported into a truck bed, railroad car or the like. Further, what has been needed is such a system which is at least capable of relatively low relief, so that material can be readily loaded onto, or off-loaded from, such a device. preferably the system is such that it is readily adaptable to a variety of warehouse arrangements, and is easily oriented for movement of cargo along a variety of paths. Further, it is preferred that such a system be capable of handling an entire bed load of cargo at once, without the need for handling of items individually, if possible.